You need to try to emulate the stage of rut. During pre-rut for example, bucks are cruising and setting dominance so light calls (light grunts and small bleat can) and light rattling will work usually. Rattling will range from light rattling like young bucks or heavy rattling to simulate full on fighting. This is coupled with a good grunt call that allows you to control the volume of grunts.
Does can be brought in using fawn bleat or small can.
Stage of rut can be observed by monitoring scrapes...frequency and quantity of scrapes. Watch the does to see how they are acting.
I have had alot of success rattling and grunting in combo to bring in bucks. Do not rattle if you see a buck unless he is far off and you want to get his attention. I would start with grunting.
Your grunts should be erratic of sorts. Try to find a sequence that works. Use your hand to manipulate the sound. If bucks are chasing and getting close to rutting...use tending grunts to full on roar as an example.
As far as walking and hunting on ground, a grunt can be a good tool to simulate another buck in area. Killed a nice mature buck walking in deep ditch grunting every so often. Move slow though and keep your eyes and ears open.
I say the more you spend in the woods watching the signs of deer will allow to call better. Knowing what the deer are doing will improve your skills.
Practice calling and rattling. Use variance.
Don't over do it by calling and rattling all the time. Be patient. Wait and see. I like to wait at least 30 mins between sequences. Make it count and have confidence with what you are doing.
Don't be discouraged. I sometimes will practice my calling skills by using different methods on young bucks. I once called in the same buck three times using different methods but you see what will work and grow confidence. It is not about killing all the time.
If you around alot of deer activity especially around alot of does...keep quiet. They will usually do the work for you naturally. I have ruined my share of hunts by calling when I didn't have to.
Good luck